Xia Jiangbao, Zhao Ximei, Chen Yinping, Fang Ying, Zhao Ziguo
Binzhou University, Shandong Provincial Key Laboratory of Eco-Environmental Science for Yellow River Delta, Binzhou 256603, China.
PLoS One. 2016 Jan 5;11(1):e0145828. doi: 10.1371/journal.pone.0145828. eCollection 2016.
Groundwater is the main water resource for plant growth and development in the saline soil of the Yellow River Delta in China. To investigate the variabilities and distributions of soil water and salt contents at various groundwater level (GL), soil columns with planting Tamarix chinensis Lour were established at six different GL. The results demonstrated the following: With increasing GL, the relative soil water content (RWC) declined significantly, whereas the salt content (SC) and absolute soil solution concentration (CS) decreased after the initial increase in the different soil profiles. A GL of 1.2 m was the turning point for variations in the soil water and salt contents, and it represented the highest GL that could maintain the soil surface moist within the soil columns. Both the SC and CS reached the maximum levels in these different soil profiles at a GL of 1.2 m. With the raise of soil depth, the RWC increased significantly, whereas the SC increased after an initial decrease. The mean SC values reached 0.96% in the top soil layer; however, the rates at which the CS and RWC decreased with the GL were significantly reduced. The RWC and SC presented the greatest variations at the medium (0.9-1.2 m) and shallow water levels (0.6 m) respectively, whereas the CS presented the greatest variation at the deep water level (1.5-1.8 m).The RWC, SC and CS in the soil columns were all closely related to the GL. However, the correlations among the parameters varied greatly within different soil profiles, and the most accurate predictions of the GL were derived from the RWC in the shallow soil layer or the SC in the top soil layer. A GL at 1.5-1.8 m was moderate for planting T. chinensis seedlings under saline groundwater conditions.
地下水是中国黄河三角洲盐碱土地区植物生长发育的主要水资源。为研究不同地下水位（GL）条件下土壤水盐含量的变异性和分布情况，在六个不同的地下水位条件下建立了种植柽柳的土柱。结果表明：随着地下水位的升高，相对土壤含水量（RWC）显著下降，而不同土壤剖面中的盐分含量（SC）和土壤溶液绝对浓度（CS）在最初升高后下降。地下水位1.2 m是土壤水盐含量变化的转折点，它代表了能使土柱内土壤表层保持湿润的最高地下水位。在地下水位1.2 m时，不同土壤剖面中的SC和CS均达到最高水平。随着土壤深度增加，RWC显著升高，而SC在最初下降后升高。表层土壤层的平均SC值达到0.96%；然而，CS和RWC随地下水位下降的速率显著降低。RWC和SC分别在中等水位（0.9 - 1.2 m）和浅水位（0.6 m）时变化最大，而CS在深水位（1.5 - 1.8 m）时变化最大。土柱中的RWC、SC和CS均与地下水位密切相关。然而，不同土壤剖面中各参数之间的相关性差异很大，对地下水位最准确的预测来自浅层土壤层的RWC或表层土壤层的SC。在盐碱地下水条件下，1.5 - 1.8 m的地下水位对种植柽柳幼苗较为适宜。
